1. Introduction
In this tutorial, we’ll review the differences between Application Servers and Web Servers. Firstly, we’ll define the terms and describe them. Next, we’ll review how Application Servers and Web Servers work. Then finally, we’ll highlight the differences between the two.
2. Introduction to Servers
Before we delve into application servers and web servers, let’s first review servers. Servers are computing devices whose main function is to provide a service or functionality to other devices. These other devices are usually called clients because they request services from the server.
Servers usually run programs that enable them to continually provide services to their client. There are different types of servers in existence today, some are specialized while some provide one or more different types of services. These include application servers, and web servers, which we’ll cover in this article. Some other types of servers are database servers, file servers, and DNS servers.
Before we delve into application servers and web servers, it is important to note that more often than not, these two work together to provide some functionality to client devices.
3. Application Servers
An application server refers to a server that provides functionalities to clients. It serves as a container to house various applications that are used by one or more client devices. Due to their ability to host different applications, application servers are seen as a way to manage and organize applications in a network.
For instance, suppose we have a university network and a number of desktop computers used by students and staff in the university. Now, suppose we have a number of applications that are commonly used in the university. Instead of installing applications on each device, we can install them on a server. Clients can then be configured to request access to these application functionalities from the server.
Some popular examples of application servers are Apache TomEE, Oracle WebLogic, GlassFish, WebSphere, and WildFly.
3.1. How Do They Work?
To illustrate how an application server works, let’s go back to our example of the university network. Suppose student X in the university needs to use a word processor. The student interacts with some graphical user interface to open the word processing application. A request is sent to the application server to give access to student X’s device:
The server receives the request and generates a response to the client’s request. The response in this context would be access to the word processing application. The response is sent to student X’s device and the student can now use the word processor.
As a result of the type of requests and the number of applications received and housed by the application server, it is designed to handle many requests at a time through load balancing. In addition, an application server is built to be fault tolerant to allow the server to function as normal with the occurrence of faults.
4. Web Server
A web server on the other hand is a server that provides web functionalities to clients. Unlike the application server, the web server is specialized to deliver web content only. The web server can be seen as a container that houses many web pages. For example, the Baeldung website is hosted on a web server somewhere over the internet, which allows different users access to the content on the website.
Web servers are an integral part of web development as they provide a centralized way of hosting and managing websites. Some well-known examples of web servers are Apache Tomcat, Jetty, Microsoft’s Internet Information Services, and Nginx.
4.1. How Do They Work?
Going back to our example of the university network. Suppose we have a staff management website within the university’s website that is hosted on a web server. Now suppose a staff member needs to enter their details on the staff management website. On their device, the staff member types the website site address in a web browser like Google Chrome or Mozilla Firefox:
This translates to an HTTP request that will be sent to the web server. On the web server, the client request is received and the specific HTML page is retrieved. The web server responds by displaying the web page of the staff management system on the client’s device.
Unlike application servers, web servers do not utilize as many resources as applications because their task is to simply host and render web pages. In addition, fault tolerance is not a design priority.
5. Differences
Now let’s look at the differences between the two.
Application Server
Web Server
Provides application functionality
Provides HTTP functionality
Uses HTTP along with other communication protocols
Uses HTTP protocol
Fault-tolerant
Not as fault-tolerant
Utilizes a lot of resources to manage client requests
Utilizes fewer resources
6. Conclusions
In this article, we’ve discussed the difference between application servers and web servers. Application servers can render many services in the form of applications to clients. On the contrary, web servers can only provide web content as a service.
Most importantly, an application server can be connected to a web server to provide services to clients. For instance, a web server can render requests for web pages while the application server manages the interactions between the client and the web pages. Alternatively, we can also have a web server incorporated inside an application server